International Journal of Computer Science and Telecommunications [Volume 1, Issue 1, November 2011]
1
An Autonomous Robot Framework for Path Finding and
Obstacle Evasion
ISSN 2047-3338
Imran Sarwar Bajwa1, Natasha Nigar2 and M. J. Arshad3
1
2,3
School of Computer Science, University of Birmingham, UK
Faculty of Electrical Engineering, University of Engineering and Technology, Lahore
[email protected]
Abstract— The modern growth of computer and its related
hardware is consequence of the invention of the transistor. The
advent of transistor principally revolutionized the hardware
engineering by reducing the hardware size and increasing the
efficiency. Now, we are swarmed in with the influx of
sophisticated computer gadgets and communication devices,
combining ingenious ideas and state of the art designs. When the
history of world would be written surely out contemporary age
would be called the age of science and technology. The marvels of
science and technology has not only bewildered human minds but
also brought convenience and quality to human life. Our project
is continuation of this tradition of science. We have endeavored
to design an autonomous path tracker vehicle. It has limitless
possibilities of usage and it would certainly become a future
workhorse. It can be used to detect the theft vehicles.
Autonomous robot for path finding and obstacle evasion is a
vehicle, which follows the path in two different ways, which are:
i) Line Follower – It is a vehicle, which is used to follow the
reflecting line drawn on the floor. It captures line position with
IR sensors. The sensors will be mounted at front end of the robot,
ii) Obstacle Handling – When an obstacle is appeared on the
following line we will detect through a sensor.
Index Terms— Robot, Path Tracking, Obstacle and Vehicle
sensors [5] or for imaging processing image sensors can also
be used. The sensors with a high resolution are required to
sense the path [11]. It will use steering mechanism that will
steer the robot to track the line. There will be two line styles
that a line follower can adapt, first is the white stripe on black
surface and second is the black stripe on white surface. The
autonomous robot for path finding and obstacle evasion will
continue its movements if it does not find the edge of the line.
However the robot will automatically stops if the edge of the
line is ended.
When robot is moving and it detects an obstacle in the
following path then it will decide what it does, either move
move left, right or to stop.It will also handle the T-slot and
same angle problem. A feed back system will also be provided
by measuring the distance of the path followed/covered by the
robot.
The rest of the paper is structured as the section 2 describes
the related work done in the field of path finding/tracking and
obstacle detection. The used approach that explains the
presented approach for autonomous path finding and obstacle
evasion is described in section 3. Section 4 presents the
conclusions of the presented research in the paper with the
possible future work.
I. INTRODUCTION
A
UTONOMOUS robot for path finding and obstacle
evasion is a vehicle, which is used to follow the path
autonomously. A typical approach for path finding is
Autonomous Line Follower (ALF) [1], [3], [4] and such
approach involves discrete logical symbols and continuous
signal. In this paper, we present a new control approach based
on symbols and this approach is incorporated so that a robot
may follow a line or stripe. To sense the barriers and obstacles
in surrounding, the robot comprises of various sensors such as
a low-resolution sensor and an actuator [2]. Major issues
investigated in this research were the control of robot so that
the robot may follow a control stripe.
The autonomous robot for path finding and obstacle evasion
is able to follow a control stripe sketched on the surface, robot
is placed. The presented robot captures line position with IR
sensors, while these sensors are escalated at the front of our
robot. Several numbers of photo-reflectors can be used as IR
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II. LITERATURE REVIEW
A few path finding/tracking algorithms have been
introduced in last two decades. Some of the famous algorithms
are the Pure Pursuit [6]. [7] and the Follow the Carrot [8].
These algorithms utilize the spatial information for the sake of
computation of the guiding commands and assist a robot in
following a given path or stripe. However, both these
algorithms do not often consider the actual curves of the target
path/stripe. Due to this short coming of these both algorithms,
they provide with less accuracy.
Vector pursuit [9] is another path tracking method that is
based on a theory originally presented by R. S. Ball in the year
1900. The Ball’s theory is typically employed to manifest the
movement of an object with respect to the targeted coordinate
system.
Another approach was also presented by T. Hellstrom [10].
The presented approach was using the recorded orientation
Imran Sarwar et al.
and steering commands to decide the direction in which the
robot moves. One type of vehicles are Automated Guided
Vehicles (AGVs) [1], [3] those are outfitted with sensors and
by using the sensors, such vehicles can follow a path. Such
robot vehicles can be used for various purposes especially in
factories in manufacturing plants, transportation purpose, etc.
Such vehicles are not only cheap in cost but also more
effective and efficient.
All the above discussed approaches, methods and
algorithms are not efficient in terms of tracking the curved
lines or paths. We aim to overcome this short coming of the
existing approaches and present a new robust technique.
III. RESEARCH METHODOLOGY
This section presents a novel approach for path detection
and obstacle evasion. The presented approach is based on a set
of traced routs and commands for the guidance of robot. The
presented approach uses algorithm that covers three typical
actions and each action is accountable for the respective facet
of path finding. Afterwards the result of the presented
approach attainted from the simulated and physical
autonomous robot are evaluate in comparison with the other
available approaches used for constructing autonomous robots
such as the Pure-Pursuit algorithm [6], [7] the Follow-theCarrot algorithm [9] and the Recorded Orientation and
Steering Commands algorithm [10]. The evaluation of results
manifests that our approach is considerably perks up the
efficiency and affectivity in the research domain of path
finding. The architecture of the presented research is shown in
figure1.
We have tried to achieve the two types of path tracking.
Firstly we try to follow the path which is given in the form of
reflecting or black line and secondly a path is given by the
vehicle driven by the user and then another vehicle will follow
this path.
We have divided our whole project in two parts which are
given below:
i.
ii.
iii.
iv.
2
Rx, Tx optocouplers
H-bridge
A T89C51 Microcontroller
LM324 N
For the implementation we have used the algorithm given
below.
• if current is passing from left sensor which is a
optocoupler then the current will pass to the left motor
and vehicle will turn left
• if current is passing from right sensor then the right
motor will turn on and vehicle will turn right
•
if no current is passing then it means no reflecting
surface is present and vehicle will stop
B. Obstacle Handling
When an obstacle is appeared on the following line we will
detect through a sensor. All the distance covered by the robot
will be displayed on the LCD screen using the encoder and Ushaped sensors [12].
i) Line Follower
ii) Obstacle Handling
A. Line Follower
It is a vehicle, which is used to follow the reflecting line
drawn on the floor. It captures line position with IR sensors.
The sensors will be mounted at front end of the robot [10]. In
line following part we have tried to achieve that a vehicle
should move on a path given by reflecting line. This line can
be given on the ground or on paper and then vehicle is left free
on that line. Vehicle will itself follow the line sensing it
through sensors built on it. As mentioned in abstract that this
vehicle will follow a particular line which may be a colored or
reflecting line with respect to your project. We have used in
our project a reflecting line so a general algorithm for this is
given in coming topic.
Automated Line Detector has two parts; one is hardware
and other is software. In the hardware we have used the
following components for the construction of Line Detector:
Fig. Proposed System Architectural Diagram
C. Technical Specifications
This vehicle consists of the following components:
• Vehicle body
• Microcontroller
• Dc motors for driving the robot
• Sonar sensors to detect the objects in front of the
vehicle
• Relays for driving the motors
International Journal of Computer Science and Telecommunications [Volume 1, Issue 1, November 2011]
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2). LM324 Features and Applications
The Fig. 2 shows the different components of LM324.
i). Features
•
Operation from single or dual supply
•
Unity gain bandwidth
•
DC voltage gain
•
bias current
•
offset current
•
offset voltage
ii). Applications
Fig.2. LM324 Circuit Diagram
D. Testing
The following tests are performed during the execution of
the project:
• Handling the T-Slot problem [13]
• Moving the robot at 45 degree
• When a line ends then robot will move backward, left
or right according the condition given by our program
E. Difficulty Encountered
•
•
•
•
Not exact measurement of the sensing ability of the
sensor
Problem Handling the T-Slot
Controlling the speed of the motors
Object detecting ability of the sonar sensor
F. Microcontroller
A microcontroller is a computer-on-a-chip, or, if you prefer,
a single-chip computer. Micro suggests that the device is
small, and controller tells you that the device might be used to
control objects, processes, or events. Another term to describe
a microcontroller is embedded controller, [14] because the
microcontroller and its support circuits are often built into, or
embedded in, the devices they control.
1). Proteus Diagrams
Fig. 3, Fig. 4 and Fig. 5 show the circuits diagrams for
(Optocoupler and LM324), [15] (Line Follower and
Microcontroller) [16], and (Optocoupler) [17], respectively.
•
Summing amplifiers
•
Multivibrators
•
Oscillators
•
Transducer amplifier
•
DC gain blocks
IV. CONCLUSIONS
Following are always an important in every era of life.
We have tried to achieve this in autonomous path tracker it
will track the path in following two ways.
A line follower will follow a reflecting line by
sensing it through sensors and control the vehicle
on the path which is given by user through
reflecting line on ground or on anything else.
Secondly it will detect the obstacles using ultrasonic sensors and cross over them and again will
come on the path given by reflecting line.
A vehicle will following an ascender that will
send the path to the follower, follower will follow
that path. This is done using storing the signal
values and particular time for which a value is
retained is stored in the memory of controller and
when there is no signal interrupt from user then
all of the data from memory contents is sent to
the memory of the other controller. Then this data
is executed by the follower which results in
following the same path that is followed by the
leader vehicle.
• Future Enhancements
Enhancements can be made with every perspective.
Vehicles can be provided with Cameras to send not only path
but also the nature of the path. Through camera it will send the
visualization about the path. Through visualization it will also
cover up the moving objects and then all control can be put up
through these cameras and enhancement due to moving
objects can be achieved.
Imran Sarwar et al.
Fig. 3. Optocoupler and LM324 Diagram
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International Journal of Computer Science and Telecommunications [Volume 1, Issue 1, November 2011]
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Fig.4. Line Following Diagram
Fig. 5. Microcontroller and Optocoupler Diagram
http://www.powerdesigners.comllnfo W eb/desi gn center/artic
les/P WM/p wm.shtm.
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